This is the 7722nd most frequent German word.
hamaguchi
The word "hamaguchi" is not German; it is a Japanese surname.
In this sentence, 'Hamaguchi' is used as a proper noun referring to an author.
Ich habe das Buch von Hamaguchi gelesen.
I read the book by Hamaguchi.
Here, 'Hamaguchi' describes a specific named method, implying an association with someone named Hamaguchi.
Die Hamaguchi-Methode ist sehr effektiv.
The Hamaguchi method is very effective.
In this example, 'Hamaguchi' is used to identify a person by name, a scientist from Japan.